Assessment of Heavy Rainfall-induced Natural Hazards in Alpine environments: The Experience of the Interreg III-B Project CatchRisk
by
Manfred Thuering
Istituto Scienze della Terra, Scuola Universitaria Professionale della Svizzera Italiana

In the last years the Alpine area may have experienced an intensification of flood and slope instability phenomena caused by an increase in frequency and intensity of heavy rainfall events, leading to territorial damage and losses of human lives.

Several Alpine regions have developed different methodologies to assess the hazard and risk of events which are linked to heavy rainfall, such as floods, superficial landsliding, debris flows and rockfalls. The demand of an exchange of know-how arose among the Alpine regions; it should enhance the creation of operational tools of common hazard assessment procedures and territorial management that can be applied on catchments with different characteristics and in different contexts in the Alpine space.

In 2002, the European Community launched the project Catchrisk, which was realized within, and partly financed by the European Interreg III-B Alpine Space initiative. The project's main goal was to enhance the communication between the regions of the Alpine space and to create common approaches for the definition of hydro-geological risk scenarios on the scale of hydrological catchments, their alluvial fans and main river courses. Particular attention was given to mass transport processes, such as rockfalls, shallow landslides, debris flows and river floods.

Within CatchRisk, where representatives of 11 regions of the Alpine space from 4 nations cooperated, the topics were addressed to assess---among others---flood hazards, the triggering of shallow landslides, debris flow expansion on alluvial fans and the reach of rockfalls. A particular effort was done to develop methodologies within GIS (geographical information systems) environments and to define risk scenarios. The efforts had the main final goal to mitigate the impact of these natural hazard phenomena on the territory and draw conclusions on the land use. The knowledge exchange and results of CatchRisk are documented in a scientific report and in guidelines for public administrations and professionals.

In this presentation the project CatchRisk is outlined, focusing on its main goals: interregional exchange and communication and presents some of the developed tools for hazard and risk assessment within hydrological catchments, alluvial fans and main river courses---the model environment of the Alpine space.

Particular attention is given to the activities developed in the working group which concentrated on the processes, which develop within a catchment basin: rockfalls, superficial landslides and debris flows. The reach of rockfalls was assessed using a statistical approach, the method was implemented in a GIS environment. The triggering of superficial landslides was studied using a regional model based on a statistical approach. Also, GIS-models were developed and implemented to study the triggering of superficial landslides, based on a geotechnical-hydrological raster model. A debris flow monitoring and alert system was installed on a catchment basin prone to this type of hazard.

Date received: July 27, 2005

Copyright © 2005 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caqy-69.